Despite only being tested on 1.16.*, this may work on other versions. If so, let me know!
This plugin automatically converts & color codes to the traditional ยง color codes which signs require, but cannot be pasted into. The plugin is extremely lightweight at only 6Kb and is optimised to keep your server running smoothly, so you can shrug off the new addition of this plugin without the fear of it causing any compatibility issues with other plugins.
Commands /sign reload - reloads the config.yml
Configurable features - Use permission or not - Optional 'no permission' messages